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Open Source Email Archiving: The Guide for Audit-Proof Archiving in 2024

E-Mail Letter

The essentials in brief


Open Source Email Archiving: The Basics

What is e-mail archiving?

E-mail archiving refers to the long-term and unchangeable storage of mails after they have been processed in the mailboxes by the respective person.

In addition, mail archiving stipulates that original digital data must be stored in its original form without being compressed. Electronic archiving must also be audit-proof.

When archiving mail, Microsoft Exchange first manages the distribution of messages to the correct mailbox. In the next step, the user can then decide whether to use Outlook's integrated archiving or to resort to a revision-proof solution.

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Open-Source Email Archiving

Why e-mail archiving?

Mail communication is an integral part of many employees in almost every company. Therefore, it is obvious that the processed mails must be stored in a legally secure manner.

Since July 2011, sending invoices by unsigned e-mail has also been permitted. Thus, many mails, as well as business e-mails, fall under commercial law and thus the legal requirements of the German Fiscal Code (AO), the GoBD, the GoBS, GDPdU & the German Data Protection Regulation (DSGVO).

The digital e-mail is thus legally equivalent to the paper document. In addition, mail archiving also offers all the other advantages that are possible when working with a DMS. For example, distribution copies no longer need to be created and the risk of document loss is minimized.

What are the retention periods for archiving emails?

The decisive factor for the duration of the retention periods for e-mails is their content. The same legal requirements apply here as in paper format. According to the tax code of the Federal Ministry of Finance, a period of 6 years is provided for the following exemplary documents*:

  • received business letters
  • Reminders
  • Accepted offers

The following business mails must be retained for at least 10 years*:

  • Invoices
  • Tax returns
  • Inventories
  • Profit and loss balance sheet
  • Logbook

* Quelle: Bundesministerium der Finanzen (2020). The list described is not complete and serves only as an example for illustration. It may not apply outside of germany.

retention periods

The practice of mail archiving in companies

How does email archiving work in Microsoft Outlook?

If mails do not have to be archived in a legally secure manner, native archiving of Outlook may be sufficient for private use. Outlook has automatic archiving for standard folders (Inbox, etc.) with various deadlines. For example, the inbox is automatically archived for 6 months.

Manual archiving of individual e-mails is also possible. In this case, an archive folder must first be created and then the corresponding entry selected by right-clicking so that the relevant emails are subsequently archived.

How do you archive mails with a document management system in an audit-proof manner?

Document management systems (DMS) and enterprise content management systems (ECM) offer solutions for this. bitfarm-Archiv document management, for example, allows direct connection to Microsoft Outlook and offers various options there, ranging from manual archiving by the user to fully automatic archiving of the entire mailbox. In the following video we show you the archiving of mails and further options for document import. 

There are also interfaces for many other e-mail systems that enable audit-proof archiving as required by the GoBS and GDPdU, for example Tobit David, Lotus Notes, Thunderbird, Kerio and many others. POP3 and IMAP4 accounts can also be archived in an audit-proof manner with the help of the bitfarm-Archiv POP3 connector - and optionally processed directly via the DMS.  

If, for example, one takes a POP3 account "invoices@company.com" and communicates this to the suppliers as an e-mail address for digital invoices, then incoming invoices can be passed here immediately to the responsible clerk for checking, depending on the supplier, and then to the accounting department.  

The incoming invoice workflow, which normally takes place with paper invoices, is thus also implemented 1:1 for e-mail invoices. In the end, it hardly matters to the DMS whether an invoice was scanned as paper or received as a PDF via e-mail. The DMS also offers the option of sending your own invoices automatically by e-mail.

In 2 steps to audit-proof e-mail archiving with bitfarm-Archiv

Our open-source DMS bitfarm-Archiv has a direct connection to Outlook and acts as an add-in in the associated bar. For a mail archiving from Outlook usually only the following steps are needed: 

1. choice between automatic or manual archiving

2. archiving of the document in the client 

In the first step, the user must choose between automatic and manual archiving. In the case of manual archiving, the user can also decide on additional options (target archive, etc.).

outlook automation

After pressing one of the two buttons, the mail is sent directly to the document management system. In bitfarm-Archiv these are stored in the importer by default. Here the user then has the possibility to determine the target archive and further options. 

By clicking on the "Archive" button, the mail is stored in the archive in an audit-proof manner. In Outlook, this is automatically marked so that the user can see at a glance which mails have already been archived.

Mail Archiving Importer

Best practices for open source e-mail archiving

It often happens that not the whole mail is needed in the archive, but only the attached files. In this case, it is a good idea to archive only these, as this is also sufficient according to GoBD. This way, the complete mail does not have to be archived, which prevents the DMS from being filled with redundant files. This also facilitates future searches in the system, since only the required data is archived. 

In bitfarm-Archiv the button "Attachments only" can be used for exactly this purpose. By clicking the button, all attachments of the selected mail are automatically sent to the document management system. 

If, on the other hand, only individual attachments of a mail are to be archived, this can be done by means of manual archiving. To do this, the option "Select attachments manually" must be clicked once in the corresponding tab. Subsequently, a window opens automatically under each mail, in which the attachment can be selected that is to be included in the archive.

manual archiving attachments

What other reasons are there for archiving e-mail with a DMS?

Another advantage of archiving e-mails is the relief of the e-mail server, since archived e-mails can be deleted there after a while and the databases of the e-mail systems do not become too large as a result. Especially from MS-Exchange one knows the phenomenon that large Outlook mailboxes often need a relatively long time to open. 

Also, the searchability in Outlook is not very good, neither performant nor accurate. A document management system can do this better and also searches the attachments of the e-mails at the same time.

What problems arise when it comes to data protection and e-mail archiving?

One problem with archiving all of a company's e-mails is private e-mails, which should not be archived for data protection reasons. However, the exact filtering of mail traffic between private and business is hardly possible.  

The only remedy is selective archiving by the user or a general ban on private e-mails throughout the company by the management. Then everything may be archived again - if there is still a private e-mail, the responsibility for this no longer lies on the employer.

Trivia around the topic of emails

  • The first e-mail was sent in 1971 by Ray Tomlinson to his second PC, which was right next to him

  • Approx. 2.8 million e-mails are sent worldwide per second

  • On average, people check their own email inbox 15 times a day

  • 86% of all entrepreneurs surveyed stated that e-mail is the preferred means of communication due to its clear legal status

  • In 2019, nearly 60% of all global mail was spam

Further reading: sources and interesting links

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